We present results from the study of optical broadband and X-ray properties of a large sample of active galactic nuclei (AGN) in the Groth-Westphal Strip (GWS) field. In order to determine the morphology of all objects, we obtained different structural parameters. Combining these parameters with other optical/X-ray properties, we were searching for

OSIRIS, the optical Day One instrument for the GTC, will shortly be shipped to La Palma to start the commissioning at the telescope. Some results of the final laboratory characterization of the instrument are shown, together with the upgrades that are planned to be operational after Day One. Several large programs using the OSIRIS Tunable Filters

A particularly interesting line for exploring the physical conditions of the quiet solar chromosphere is Halpha , but its intensity profile is magnetically insensitive and the small circular polarization signatures produced by the longitudinal Zeeman effect come mainly from the underlying photosphere. Here we show that the Hanle effect in Halpha

We explore the photospheric and chromospheric magnetic field in an emerging flux region. An image of the equivalent width of the He I 10830 Å red blended component shows the presence of filamentary structures that might be interpreted as magnetic loops. We point out that the magnetic field strength in the chromosphere resembles a smoothed version

The solar chromosphere is a vigorously dynamic region of the sun, where waves and magnetic fields play an important role. To improve chromospheric diagnostics, we present new observations in Ca II 8542 carried out with the SST/CRISP on La Palma, working in full-Stokes mode. We measured Stokes line profiles in active regions. The line profiles

X-ray binaries are excellent laboratories to study collapsed objects. On the one hand, transient X-ray binaries contain the best examples of stellar-mass black holes while persistent X-ray binaries mostly harbor accreting neutron stars. The determination of stellar masses in persistent X-ray binaries is usually hampered by the overwhelming